Two point charges +8q  and -2q are located at x = 0 and x = L respectively. The location of a point on the x-axis at which the net electric field due to these two point charges is zero is

The net field will be zero at a point outside the charges and near the charge which is smaller in magnitude.Suppose E.F. is zero at P as shown. Hence at P; k⋅8q(L+l)2=k⋅(2q)l2⇒I=LSo distance of P from origin is L + L = 2L.